US4374398A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiplexed television audio signal receiver
Assignee: Panasonic Holdings Corp
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Filing: 1981-04-08
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Granted: 1983-02-15
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Expires: 2001-04-08
Abstract
Abstract In a receiver of the type capable of receiving a second or third subchannel audio signal which contains no pilot signal and which is multiplexed with the television audio signal, only the subchannel signal frequency components pass through a band-pass filter the output of which is fed to a clipper circuit so that the carrier level of the output is suppressed. The output of the clipper circuit is detected whether the subchannel signal is present or absent or subchannel signal is increased so that a squelch circuit is turned off and a display device is turned on or vice versa.
Inventors
- 👤 Akira Yamashita
- 👤 Nagai Hiroyuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:48
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/60; H04N5/607
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
104 words
A multiplexed television audio signal receiver of the type capable of receiving by the inter-carrier system the television multiplexed audio signals comprising the main audio signal multiplexed with a second or third FM subchannel signal, characterized by the provision of (a) a band-pass filter for extracting the FM subchannel signal, (b) a clipper circuit for suppressing only the carrier level of the output from said band-pass filter, (c) a detector for detecting the output from said clipper circuit so as to detect the noise level, and (d) a squelch circuit responsive to the output from said detector for cutting off the demodulated subchannel signal.
Claim 2
Dependent Claim
104 words
A multiplexed television audio signal receiver of the type capable of receiving by the inter-carrier system the television multiplexed audio signals comprising the main audio signal multiplexed with a second or third FM subchannel signal, characterized by the provision of (a) a band-pass filter for extracting the FM subchannel signal, (b) a clipper circuit for suppressing only the carrier level of the output from said band-pass filter, (c) a detector for detecting the output from said clipper circuit so as to detect the noise level, and (d) a squelch circuit responsive to the output from said detector for cutting off the demodulated subchannel signal.
Claim 3
Dependent Claim
22 words
A multiplexed television audio signal receiver as set forth in claim 1 further characterized in that said detector is a peak-level detector.
Claim 4
Dependent Claim
44 words
A multiplexed television audio signal receiver as set forth in claim 1 further characterized by the provision of a circuit responsive to the output from said detector for turning off a display lamp which displays the reception of the subchannel signal when turned on.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-14 | 1986-08-16 | 1987-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-14 | 1990-08-16 | 1991-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-14 | 1994-08-16 | 1995-02-15 | $7700.00 | Window Closed / Lapsed |